Christopher Cox, son of state GOP chairman Ed Cox and a congressional candidate for a prime Suffolk County seat, took in nearly $735,000 in his first fund-raising quarter since he joined the race, The Post has learned.

Cox’s haul also reveals for the first time that he is self-funding to some extent — he loaned himself $500,000 as part of the first quarter of 2010, aides said. He works as a business consultant.

Cox aides said the money came from liquidating some holdings, and was all his own. He runs a consulting practice that advises on investments.

There was also a $13,000 in-kind donation, and he now has $623,562 in cash-on-hand.

Cox’s team said his average donation was $358, and there were 616 individual donations – but they said most of their haul came in contributions of less than $200.